JP 2014-84008A (Reference 1) discloses an example of a vehicle seat slide device which, by sliding an upper rail in a vehicle front-rear direction in relation to a lower rail which is fixed to a vehicle body, adjusts the position of a seat which is supported by the upper rail in the vehicle front-rear direction. The lower rail of the device includes a base portion which extends in the vehicle front-rear direction, and a pair of wall portions which are connected to end portions of the base portion in the vehicle width direction. A foreign object blocking member for suppressing the entrance of a foreign object such as a lighter into the lower rail from above is attached to the base portion of the lower rail.
In the device described in Reference 1, a snap-fit structure is adopted as the attachment structure of the foreign object blocking member to the lower rail. In other words, a through hole is formed in the base portion of the lower rail, and a protruding portion which protrudes downward is provided on the foreign object blocking member. When the through hole is penetrated by the protruding portion, a claw portion which is provided on the tip of the protruding portion is caused to abut against the bottom surface of the base portion, the bottom surface being positioned on the opposite side from the top surface which faces the foreign object blocking member. By locking the claw portion of the protruding portion with the lower rail, it is possible to attach the foreign object blocking member to the lower rail.
Incidentally, in the snap-fit structure described above, the length dimension of the protruding portion is larger than the thickness dimension of the base portion by a sufficient degree in order to cause the claw portion of the protruding portion to reliably abut against the bottom surface of the base portion of the lower rail. However, in this case, wobbling of the foreign object blocking member is permitted within a range in which the locking between the claw portion of the protruding portion and the lower rail is held. When the foreign object blocking member wobbles in relation to the lower rail, collision between the foreign object blocking member and the lower rail occurs repeatedly, and abnormal noise is generated as a result of the collision.